Steam heating system



July 18, 1950 E. P. HARRISON E'rAL- 2,515,651

STEAM HEATING SYSTEM Filed Oct. 4, 1947 6 Sheets-Sheet 1 MASTER CONTROLPUMP u f r flu/P02101 5. m 662mm Paw/Maeda,

July 18, 1950 E. P. HARRISON Erm. 2,515,651

STEAM HEATING SYSTEM Filed oct. 4, 1947 e sheets-sheet 2 rwfj 0 n 8f 66a7 m VALVE l 38 f@ :l '$6 36 l lr l lr p l\ fr '-32 37 vf 7 66 l .L i gi l 0 49 #46 6 48 I J 4? July 18, 1950 E. P. HARRISON Erm. 2,515,651

STEAM HEATING SYSTEM July 18, 1950 P. HARRISON ETAL 2,515,651

STEAM HEATING SYSTEM Filed Oct. 4, 1947 6 Sheets-Sheet 4 MASTER CONTROLTO .BOILER 'gfx-Sgam To wA-rz-:R TRMTMEN-r FROM WATER TREATMENT .BOILERflu/@1M 'nmAWMM/mzm @A4/fa a. W24/nf* www 5.

July 18 1950 E. P. HARRISON Erm. 2,515,651

STEAM HEATING SYSTEM Filed Oct. 4, 1947 6 Sheets-Sheet 5 T I S Q O B0LER ffm/@wrs wam MKM/am, @A4/We @.dm V- y- 7 z E t l July 18, 1950 E. P.l-lAn'msoN rs1-AL 2,515,551

STEAM HEATING SYSTEM Filed Oct. 4, 1947 6 Sheets-Sheet 6 CON DE NSATEPUMP Patented July is, 195o STEAM HEATING SYSTEM Elmer Paul Harrison,Chicago, lll., Orville A. Hunt, Oklahoma City, Okla., and Louin Tiller,Chicago, lll., assignors, by 4direct and mesne assignments, toReconstruction Finance Corporation, Chicago, Ill., acorporation of theUnited States Application october 4, 1947, serial No. 117.894

1s claims. y(01.237-9) This invention relates to heat exchange systemsemploying steam for processing materials, auch as steam systems inlaundries, paper mills., and other industries.

The invention pertains particularly to irnprovements in steam systemssuch as described in the Harrison and Hunt Patent No. 2,366,332, thecopending application of Harrison and Hunt Serial No. 581,586, led March8, 1945, entitled Heat Exchanger System. and the abandoned applicationof 'Iiller and Hunt Serial No. 762.628, filed July 22, 1947, entitledSteam System. The present application is a continuation in part cf theabandoned application of Harrison et al., Serial No. 701, 252, iiledOctober 4, 1946, entitled Steam Heating System." The four mentioneddisclosures are hereby incorporated in the present disclosure byreference. insofar as consistent herewith.

Other copending applications disclosing the subject matter relatedhereto are: S. N. 78,605, led February 26, 1949; S. N. 78,843, filedFebruary 28, 1949; S. N. 78,842, filed February 28, 1949; S. N. 78,604,led February 26, 1949; and S. N. 80,802, flledFebruary 28, 1949.

A steam system of the type here involved is characterized by openchannels for continuous flow from the steam supply through the equipmentsteam chests to the end of a return line in combination with thermostatmeans to release fluid from the return line into a region of lowerpressure in a controlled manner to maintain a desired velocity level oraverage throughout the system. In the preferred practices of theinvention a master control for regulating such release from the returnline includes a receiver for fluid returned from the steam system and/ornew water for the system'.

The volume or rate of fluid release from the return side of the steamsystem is sufficient to minimize condensate in the system and tomaintain a high rate of heat transfer to the material being heated. Themaster control is adjustable and the optimum rate of release for whichthe master control is set varies among` installations. The act ofadjusting'the master control with respect to the rate of release fromthe return side of the system is aptly referred to as tuning the mastercontrol unit. The inherent range of adjustment should be extensive tom'ake the mas- 2 ter control readily adjustable to different steamsystems and different operating conditions.

One of the general objects of the present invention is to provide anaugmented tuning range for the master control and to provide means andmethods for applying the principles of the invention to a wide range ofsteam systems.

In some practices of the invention this general object is attained bythe introduction of a modifying factor in the functioning of themastercontrol. One example isthe introduction of a cooling fluid to modify theaction of a thermostat-controlled valve that controls the release offluid from the return side of the steam system. Another example ofintroducing a modifying factor is the use of a heat exchanger to causecondensation of vapor in the return side of the system upstream from'the thermostat valve so that velocity of flow through the steam systemis promoted not only by the action of the thermostat valve but also bythe action of the heat exchanger.

In other practices of the invention a modifying factor and a newcombination of functions is provided by regulating the rate at which uidis released from the receiver. The pressure in the receiver isdetermined, on the one hand, by the rate at which fluid is released intothe receiver from the return side of the system and, on the other hand,by the rate at which iluid is released from the receiver. The thermostatfor controlling release into the receiver responds to temperaturechanges in the receiver, which temperature changes, of course, vary withpressure changes. The temperature setting of such a thermostat is onetuning factor and the rate at which fluid is released from the receiveris a modifying factor which, taken with the first factor, affords a widerange of adjustment.

The fluids released from the receiver may be utilized in any desirablemanner. For example, steam and/or condensate from the receiver may beused for preheating and deaerating make-up water. In this regard oneembodiment of the invention comprises a novel arrangement of a receiverand a remote deaerating feed water heater. x

A further object of the invention in certain of its practices is tofavor the creation of pressure changes, velocity surges and pulsationsin the system for the sake of certain beneficial results.

Other objects and advantages of the invention will be apparent in thedescription to follow, taken with the accompanying drawings.

In the drawings, which are to be regarded merely as illustrative:

Fig. 1 is a diagrammatic view illustrating one embodiment of theinvention;

Fig. 2 is a diagrammatic view showing certain details of the mastercontrol in Fig. 1;

Fig. 3 is a fragmentary sectional view showing how an orifice member maybe employed in the system;

Fig. 4 is a fragmentary diagrammatic view indicating how air instead ofwater may be used for the cooling fluid;

Fig. 5 is a fragmentary diagrammatic view of a master control employedin a modified form of the invention;

Fig. 6 is a diagrammatic view representing a steam system incorporatingthe master control of Fig. 5.

Fig. 7 is a fragmentary view similar to Fig. l showing how thearrangement shown in Fig. 1 may be modified;

Y Fig. 8 is a diagrammatic view of another embodiment of the invention;

Fig. 9 is a diagrammatic view of an embodiment of the inventioncombining a receiver under pressure with a remote cooperating deaerator;

Fig. 10 is a diagrammatic view of an embodiment of the invention using ajet-compressor; and

Fig. 11 is a diagrammatic cross-section of the jet-compressor.

Fig. 1 shows, by way of example, the invention incorporated in paperdrying machinery having a plurality of heat exchangers in the form ofdriers or cylinders I8. The web of paper to be dried moves in thedirection indicated by the arrow II and makes successive contact withthe rotating cylinders I6.

A boiler I2, or equivalent steam source, delivers steam through asuitable supply line I3 to a supply header I4, and the various cylindersI0 are connected in parallel to the supply header by suitable feed pipesI5. Each of the feed pipes I5 communicates with the correspondingcylinder Il through the trunnion of the cylinder, as indicated in Fig.2, and condensate is discharged from the cylinder through a, suitabledischarge pipe I1 that extends through the same trunnion of the cylinderand through a portion ofthe feed pipe. The discharge pipe I1 of eachcylinder leads to a suitable return header I8.

In accord with a common practice it is contemplated that the outflowfrom each of the cylinders Il will be restricted relative to the inflowto the cylinder for the purpose of proper steam distribution among thecylinders and for maintenance of the desired pressure differentialbetween the supply -header I4 and the return header I8. In the describedarrangement the discharge pipe I1 from each drying cylinder I0 issuiliciently smaller in diameter than the corresponding supply pipe I5to provide the desired restricting eect, but in some practices of theinvention the restriction in the outflow from each drying cylinder maybe provided, either by a valve or by an orifice member. Fig. 3, forexample, shows an oriilcemember 28 in a discharge pipe 2|, the orificemember being housed in a suitable fitting, generally designated 22.

Preferably the heat exchangers or drying cylinders Il are grouped intosubdivisions or banks of cylinders. Such grouping may be accomplishedby. in effect, providing separate return headers for each subdivision.In the construction shown in Fig. 1, instead oi providing structurallyseparate return headers for the various banks we employ the singlereturn header I8 but incorporated therein suitable valves whereby theheader may be divided into functionally separate sections. Thus thetwenty-four drying cylinders I0 shown in Fig. 1 may be grouped into foursubdivisions or banks of six cylinders each by closing three valvesdesignated 25, 26 and 21.

A feature of the arrangement shown in Fig. 1 is adjustability withrespect to the grouping of the drying cylinders I8 into subdivisions orbanks. Thus,'by opening valves 25, 26 and 21 and closing valves 28, 29and 30, the drying cylinders will be regrouped into banks comprisingfour, five, seven and eight cylinders, respectively. In such regroupingit will be noted that there is a relatively small number 'of cylindersin the first bank reached by the traveling paper, which cylinders areknown as wet rolls, and a relatively large number of cylinders or dryrolls in the last bank. Since more steam is condensed on the wet end ofthe series than on the dry end, this grouping tends to equalize theamount of condensate that must be carried away from each of the returnheader sections.

The four sections of the return header I8 are connected with a mastercontrol, generally designated 3i, by means of four individual returnlines 32, respectively. As shown in Figs. 1 and 2, the master control 3lincludes a receiver tank 36, and four control or release valves 31 inthe four return lines 32, respectively, operated by four correspondingthermostats 38. The receiver tank may be at substantially atmosphericpressure, or at some pressure above atmospheric. In this instance it isassumed that a vent line 40 for the receiver tank is suitably adapted tomaintain a moderate pressure in the tank.

Each of the return lines 32 may be provided with a suitable check valve83 and a manually operable valve 84. Preferably each of the return lines32 is also provided with a suitable strainer. Fig. 2 shows a well-knownY-strainer 85 which may be flushed whenever desired by opening a valve86 in a pipe 81. As indicated in Fig. 2, the flushing action may bedirected into the receiver 36 or may be directed through a branch pipe88 to waste.

In the particular arrangement shown in Fig. 1, condensate dischargedinto the receiver tank 36 by the four return pipes 32 is conveyed fromthe tank by a pipe 4I to a pump 42, and is forced by the pump through apipe 43 to a suitable feed water tank 45. The pump 42 operatescontinuously, but whenever the liquid level in the receiver tank 36drops to a predetermined minimum level a cut-off valve 46 in the pipe 43is closed automatically by a float controlled means 41, whereupon thecondensate discharged from the pump 42 is recycled through the receiverby virtue of a by-pass line 48 equipped with a. relief valve 48. Therelief valve 49 is spring loaded to maintain a closed position, butopens in response to the pressure rise in the discharged condensate thatresults from closing of the cutoff valve 46.

New water to make up for losses in the system is delivered to the feedwater tank 45 through a supply pipe 50, the supply pipe being equippedwith a iloat controlled valve 52 that opens in response to lowering ofthe water level in the iced water tank. From the feed water tank asuitable boiler feed pump Il replenishes the boiler i2 through a feedline 5I in response to the usual automatic means (not shown) controlledby the water level in the boiler.

The specific construction of the master control 3I may be understood byreferring to Fig. 2. It will be noted that the bulb 55 of the thermostat33 that contains the usual volatile fluid for operating thecorresponding release valve 31 is in ay pipe 51 on the discharge side ofthe 'release valve, and that the pipe 51 is larger in diameter than thereturn line -on the inlet side of the release valve, so that thereleased fluid has space in which to expand. The relationship betweenthe thermostat and the valve is such that the valve closes, or at leastpartially closes, in response to increasing temperature, and opens, orat least opens to a greater degree, in response to decreasingtemperature, the relationship being adjustable to cause the valve toopen and close at selected temperatures. Thus the release will be in apulsating manner, the release being by pulsating continuous flow if thevalve merely iluctuates between two open positions and being bypulsating intermittent ilow if the valve actually closes.

The pipe 51, housing the thermostat bulb, communicates with one or moredownwardly directed spray heads 58, and it is important for the purposeof the invention that the small discharge apertures of the spray headshave suiliciently low flow capacity to restrict the outflow from thepipe 51 relative to the inflow. In other words, the discharge capacityof the release valve 31 is so much greater than the discharge capacityof the spray heads that prolong discharge from the release valve intothe pipe 51 will cause a pressure rise in the pipe. Because of thisaction the pipe 51, in combination with the spray head 58, may b e aptlytermed a pressure accumulation chamber.

The critical temperature ci' each thermostat 38, or the temperature atwhich the thermostat is adjusted to cause opening action or closingaction of the corresponding release valve 31, is above the normaltemperature of the receiver tank 36 and below the temperature prevailingin the corresponding return line on the inlet side of the release valve31, so that opening action of the release valve occurs automatically asthe temperature in the accumulation chamber drops toward the normaltemperature and closing action occurs automatically as the fluidreleased into the pressure accumulation chamber raises the temperaturetherein toward the temperature level in the corresponding return linethat supplies the valve. By virtue of this arrangement the release valvecauses pulsating flow in the system.

By way of example let it be assumed that the normal pressure of thecondensate and steam on the inlet side of the release valve 31 isapproximately thirty-two pounds, with the condensate at thecorresponding temperature of 277 F.; that the pressure in the reservoirtank 36 is on the order of six pounds maximum, with a correspondingtemperature of 230 F.; and that the thermostat setting is 255 F. Asheretofore stated, prior to opening action of the release valve 31 thepressure and temperature in the pressure accumulation chamberapproximate the pressure and temperature in the receiver tank. Uponopening action of the release valve 31, however, condensate, or amixture of condensate and steam, is introduced into the pressureaccumulation chamber in large amount and with drop in pressure. The dropin pressure, of course. causes at least a portion of the condensate toflash into steam. As a result of the fluid introduction and ofvaporization of the introduced fluid on one hand, and on the other handthe restriction of outilow by the spray apertures, the pressure in thepressure accumulation chamber rises with corresponding rise intemperature. When the temperature reaches approximately 255 or more.depending upon the lag in the operation of the thermostat, the releasevalve 31 is automatically operated in a closing direction, andimmediately the pressure and temperature in the pressure accumulationchamber recede to cause repetition of the valve-operating cycle.

Each of the thermostats 3l is tuned" or adjusted empirically to cause anoverall or average pressure readings are taken at various parts of thesystem and along the traveling paper for guidance in ascertaining theoptimum setting of each `thermostat 38. The thermostat setting israised, of course, to increase the rate of fluid release, 4and islowered to decrease the rate of release.'

` Since each valve 31 operates intermittently the increases in theoverall or average rate of release by the valve may be raised either byincreasing the frequency of the opening operations of the valve or byprolonging the periods of release or maximum release by the valve, or byincreasing both the frequency and duration of valve operation. Theraising of the temperature setting of a thermostat increases the rate ofrelease flow by both of these expedients, since the higher the relativetemperature in the pressure accumulation chamber when the valve closes,the more rapid is the subsequent drop in temperature to cause repetitionof the valve operating. cycle, and the higher the temperature requiredAto close thek valve the longer is the period required for thattemperature to be built up in the pressure accumulation chamber.Preferably a combined pressure gauge and thermometer 59 is provided toindicate the pressure and temperature prevailing inside the pressureaccumulation chamber or pipe 51.

The range of variation in the rate of fluid release by a valve 31 thatmay be covered simply by manipulating the setting of the correspondingthermostat 38, which range is adequate for many installations, islimitedby the pressure and temperature prevailing in the receiver tank 36 andthe pressure and temperature prevailing in the return line 32 above thevalve 31. On the one hand, the temperature setting` of the thermostat 38must be lower than the normal temperature above the release valve tocause the valve to be closed automatically in response to heat providedby the released fluid, and, on the other hand, the thermostat settingmust be above the normal temperature in the receiver tank 35, becauseotherwise the temperature in the pressure accumulation chamber wouldnever drop suiliciently to open the valve.

If greater iluid release or more frequent iluid release is required fora given installation than is available within the practical range ofthermostat adjustment, it is necessary to change some factor other thanthe temperature setting of the thermostat, or to introduce some newfactor. Among the factors that conceivably could be 7 changed are therate at which fluid is released at the maximum open position of thevalve and the restriction of flow by the spray nozzles. It`

has been found, however, that any change in these two respects involvesconflicting or complicating factors. For example, increasing the rate offlow through the valve at the maximum open position of the valveincreases the rate at which the temperature in the pressure accumulationchamber rises, and (thereby shortens the valve operating cycles.Decreasing the size or number of the spray apertures to hasten the risein temperature for opening action of the valve, thereby to raise theoverall rate of fiuid release, tends to defeat its purpose byrestricting the capacity of the spray heads to handle the increasedvolume.

Wherever this dilemma is met the present invention solves the problem bythe application of a cooling fluid to the thermostat 38, therebyintroducing a factor that modifies other involved factors in a desirablemanner. The application of a cooling fluid to the thermostat hastens thedrop in temperature of the thermostat following closing of the valve,and thereby increases the frequency of the valve opening operation. Whenthe valve is open to introduce the released fluid into the pressureaccumulation chamber the applied cooling fluid prolongs the period offlow or maximum flow in two ways: first, by modifying i are retardingthe heating effect of the released fluid, i. e., retarding a rise intemperature in the pressure accumulation chamber, and second, bycounteracting to an appreciable extent the flashing of the releasedcondensate with consequent retardation in the rate of pressure rise inthe accumulation chamber.

The cooling fluid may be applied in various ways in various practices ofthe invention. A feature of the particular arrangement shown in Figs. land 2 is the recycling of condensate from the receiver tank 36 for thispurpose. In the construction shown the means for recycling thecondensate includes a pipe 6U that branches from the pipe 43 between thepump 42 and the cut-olf valve 46. To insure suiicient pressure foradequate flow in the pipe 60 a pressure regulator valve 6| may beinserted in the pipe 43 beyond the cut-off valve, if desired, so thatwhen the cut-off valve is open substantial pressure on the dischargeside of the pump 42 will prevail. It is to be understood, however, thatthe pressure regulator valve 6| is not essential. The pressure settingof the regulator valve 6| will, of course, be less than the pressuresetting of the relief valve 49 in the bypass 48.

The recycled condensate may be conducted to a suitable heat exchanger62, where it is cooled by new water, the new water being supplied to theheat exchanger through a pipe 63 and being discharged therefrom into thepreviously mentioned supply pipe 50. From the heat exchanger 62 thecondensate passes into a pipe 65 which, by preference, is equipped withan intermittently operated valve 66, although such valve may be omitted.

The valve 66 may be operated periodically in any suitable manner. Theparticular arrangement shown in disclosed in the previously mentionedcopending application Serial No. 581,586, and includes a solenoid 61that operates the valve in one direction in opposition to a returnspring 68. The circuit for energizing the solenoid 61 is controlled by asuitable relay 10 in a control timer being adjusted to vary thefrequency and/or duration of the open valve periods.

The pipe 65 that is controlled by the valve 86 is in effect a manifoldfor supplying cooling uid for each oi' the four thermostats 38, thecooling fluid being supplied through four corresponding branch pipes 13equipped with individual adjustable valves 15. Preferably, as shown inFig. 2, each of the pipes 51, comprising a part of the correspondingpressure accumulation chamber, is enlarged to provide an annular space16 surrounding a jet nozzle 11 and a Venturi throat 18, and thecorresponding branch pipe 13 communicate with this annular space. Byvirtue of this arrangement the fluid released from the valve 31 draws inthe cool condensate from the branch pipe 13, and the condensateimmediately enters into intimate mixture with the fluid released by thevalve.

It is apparent that tuning of the master control 3| in the improvedarrangement is quite flexible, since both the thermostats 38 and thefour recycling valves 15 may be adjusted. In addition the cooling of thecondensate by the heat exchanger 62 may be adjustable, but usually suchadditional adjustment is not at all necessary because manipulation ofthe thermostats 38 and the valves 15 cover such a Wide range of rates offluid release. Adjustments may be made over the augmented tuning rangewith surprising precision.

Often the prevailing temperature in the receiver tank 36 is low enoughrelative to the temperature prevailing on the inlet sides of the releasevalves to make cooling of the recycled condensate unnecessary, so thatin many instances the heat exchanger 62` may be omitted. Theintermittent valve 66 may also be omitted. The use of such anintermittent valve, however, results in abrupt changes in the coolingaction and causes abrupt pressure changes in the steam system. Theabrupt pressure changes or pressure waves in the steam system have beenfound to have a highly desirable effect in increasing the rate of heattransfer in the various drying cylinders I8.

Fig. 4 indicates how air, instead of condensate, may be employed as thecooling liquid to introduce a modifying factor for increasing theinherent tuning range of the master control. The structure involved islargely identical with the structure heretofore described, as indicatedby the use of corresponding numerals to identifycorresponding parts.Instead of introducing cooling condensate into the pipe 51 to affect thethermostat 38, a blower or fan is positioned to direct cooling airagainst the exterior of the walls inclosing the thermostat 38. Obviouslythe cooling stream of air will have the same general effect as thepreviously described cooling stream of condensate, but usually to lesserdegree. The fan 80 is driven by a suitable motor in a housing 8|, andthe speed of the motor is adjustable by a suitable variable control 82.In this arrangement tuning may comprise adjusting the speed of theblower 88 alone or in addition to adjusting the settings of thethermostats 38.

The invention may be embodied in other steam arrangements, as indicatedby way of example in Figs. 5 and 6. Fig. 5 shows a master control,generally designated 89, including an upright receiver tank 90, and Fig.6is a simplified diagram illustrating how such a master control may beincorporated in a steam system.

Fig. 6 shows the master control tank 90 connected to a feed water supplypipe 9| and connected to a boiler 92 by means of a boiler feed circuit1| governed by a suitable timer 12, the u pump 83 and a pipe 94. Thepump 93 may vary in operation in response to changes in the boiler waterlevel by virtue of suitable automatic control means (not shown), or mayoperate at constant speeds subject to adjustment from time to time.

The boiler is connected by a steam linev 95 to one or more heatexchangers, Fig. 6 showing two heat exchangers 96. Instead of valves roriiice members at the outlet sides ofthe two heat exchangers, thedrawings show short lengths of relatively small pipe 91. The small pipes91 are inserted in branches of a return line 98 that carries condensateand steam from the heat exchangers to the master control 89. Preferably,but not necessarily, a receiver tank 99 is inserted in the return line98, as indicated, the receiver tank being closed from the atmosphere.Thus a clear trap-free channel is provided for the flow of steam fromthe boiler to the master control.

As shown in Fig. the master control tank 90 contains heated deaeratedwater having a normal upper level |00 determined by a float |0|controlling a valve |02 in the water supply line. Preferably an overflowpipe |03 is connected to the master control to keep the water level fromrising substantially above this upper level |00.

When the water drops in level the iioat automatically opens the valve|02 to restore the water level. An auxiliary throttling valve |04 mayalso be placed in the water line, as shown.

The new water from pipe 9| passes through a condenser unit |05 havingmultiple ducts with exterior iins, the unit serving both to condensewater vapor in the master control and to heat the new water initially. Asuitable hood |06 may be provided to cause ascending water vapor to passthrough the unit |05, non-condensable gases escaping through the vent|01 at the top of the master control.

From the condenser unit |05 the new water passes through the valve |02and then into a mixing passage or pipe |08 that terminates in aplurality of downwardly directed spray or atomizing heads |09. Themixing passage provided by the pipe |08 corresponds in function to thepreviously mentioned pressure accumulation chamber in the firstdescribed form of the invention. Preferably a drip pan l l0 is placedadjacent the mixing pipe |08 to receive heat therefrom, the drip pancatching droplets of condensate from the unit 05 and overiiowing ontothe body of water below. Heating the water in the drip pan results inthe release of non-condensable gases from 'the water.

. The return line 98 of the system is connected to an injector or nozzledirected into the mixing pipe |08, the ow of steam and condensate to thenozzle being controlled by a thermostat valve ||2 ,in the return line.The valve ||2 opens in response to lowering of the temperature in themixing pipe |08 to a` predetermined minimum and closes in response torise of the mixing pipe temperature toy a predetermined maximum, beingadjustable for various temperature settings. For such response the'thermostat valve ||2 is providedwith a control tube terminating in athermostat bulb I3 inside the mixing pipe |08. Preferably, as shown inFig. 5, the spray nozzles |09 are higher than the portion of the mixingpipe |08 housing the thermostat bulb ||3 to favor normal envelopment ofthe bulb by a residue of water whenboth valves |02 and I2 are closed.

The desired cooling fluid forintroducing the modifying factor into thetuning combination l0 may be supplied by a suitable pipe 5'. connectedwith the pipe |08 adjacent the injector nozzle I The cooling fluid maybe obtained from any suitable source and maybe circulated by anysuitable means. In the particular construction shown the condensateaccumulated in the bottom of the tank is recycled through the pipe IIIby a suitable pump |l6, and the rate of recycling fiow is controlled bya suitable valve ||1.

In the described arrangement shown in Figs. 5 and 6, the setting of thethermostat is, of course, substantially above the normal temperatureprevailing in the master control tank 89, so that in the absence of anycooling aids whatsoever the thermostat bulb |I3 would drop intemperature to a point at which the thermostat valve or release valvel|2 would be opened. A continuous cooling eil'ect on the thermostat bulbis added by the condensate continuously recycled through the pipe H5,the modifying eiiect being the same as heretofore described.

An additional cooling eii'ect which automatically varies with the heatload on the system is aiiorded by the new water that is introduced intothe mixing pipe 08 whenever the float controlled valve |02 is open. Theoperation of the valve |02 follows variations in the heat load, sinceincreasing the heat load increases the demand for new water andtherefore increases the amount of new water released into the pipe |08by operation of the float |0I. It is to be noted, moreover, thatwhenever condensate removal from the system tends to' slow down. theliquid level |00 in the master control tank 90 tends to drop thereby tocause the control valve |02 to introduce new water with consequentcooling eil'ect on the thermostat bulb. Such cooling action hastensopening of the valve ||2 to hasten the removal of the condensateaccumulated in the system. The cooling effect of the new water may beprolonged by simply throttling the ilow of the new water through thevalve |02, the throttling action being accomplished in an adjustablemanner by the valve |04. i

It is apparent that the system shown in Figs. 5 and 6 has all of theadvantages of the rst described system, and the added advantage oi'automatically releasing steam in response to the addition of new waterwhereby the release of steam is desirably increased to a substantialextent whenever the heat load on the system is increased. l

Opening and closing action of the thermostat valve I2 creates beneficialpressure pulsations and velocity surges in the steam system. To increasethe number of such pulsations and surges, suitable means may be providedto continually and automatically interrupt the flow of new water whenthe float |0| is down. Fig. 5 shows a solenoid valve |20 in the watersupply pipe 9| for this purpose.

The solenoid valve |20 is in series with an automatic electric timer|2|, and a mercury switch |22. The circuit is traced as follows: lead|23, solenoidvalve |20, wire |24, timer |2|, wire |25, mercury switch|22, and lead |26.

The mercury switch |22 is mounted on the Iioat control mechanism to rockto a circuit closing position whenever the float I 0| drops sufElcientlyto open' the float valve |02. Thus whenever the float valve |02 opensthe solenoid valve |20 is operated to repeatedly interrupt the flow ofcooling water to the thermostat bulb H3. Such intermittent water flowcauses the thermol1 stat valve ,.l I2 toopen and close repeatedly whilethe iloat is down.

The timer |2| may be of any suitable type. In one practice, the timer|2| is a well known control device that is adjustable to divide a 30second period into an open valve period and a closed valve period in anydesired proportion. For example, the solenoid valve may open for tenseconds and close for 20 seconds in repeated cycles of operation.

Fig. 7 shows an arrangement for using water other than recycledcondensate for cooling the thermostat bulb. If soft water is availablefrom the general water supply or if it is feasible to use water that hasbeen treated for use in the steam system, this arrangement is suggested.

The structure shown in Fig. 7 is largely identical with the structureshown in Fig. 1, as indicated by the use oi.' corresponding numerals todesignate corresponding parts. The new water i'or cooling the bulbs issupplied through the previously described cooling water manifold 65, andmay be periodically interrupted by the timercontrolled valve 66. Thecondensate mixed with the introduced cooling water in the receiver isdelivered to the pipe 43 by the previously mentioned pump 42 asheretofore described.

The receiver 36 may be under substantial pressure and the pipe 43 maylead directly to the boiler so that the condensate throughout the steamcondensate cycle is maintained at relatively high pressure to avoid heatlosses by excessive flashing. In all practices of the invention, theiluid released from the receiver by the vent arrangement may be used forvarious heating purposes. Examples of such use will be described later.

'lhe purpose of Fig. 8 is to illustrate how the action of cooling wateron thermostat bulbs for promoting and controlling velocity in the returnlines of the steam system may be supplemented by heat exchangers in thereturn lines for the same purpose.

Fig. 8 shows a master control 3| including a receiver 36 provided with avent release |30. The vent release may serve, for example, to maintain apressure on the order of 10 to 30 pounds in the receiver. The usualreturn lines 32 are connected with the receiver 36 through the usualthermostat-controlled valves 31 and water for cooling the thermostatbulbs is supplied through a cooling header 65 as heretofore described.

Each of the return lines 32 is provided with a heat exchanger |3|through which cooling water ilows for the pllrDOse of causingcondensation of steam in the return line. Such condensation means thatthe iluid shrinks to only a fraction of its vapor volume, and, ofcourse, such contraction in volume promotes flow in the return line.

It is apparent that a cooling uid from any suitable source may beemployed in the series of heat exchangers |3I and that the cooler themedium the greater the flow-promoting eHect. In the particulararrangement shown in Figure 8, the cooling fluid is supplied by aconventional water treating apparatus which may not only treat the waterbut also deaerate the water.

The treated water under pressure and at, say, 220 F. flows through apipe |32 having two branches |33 and |35. The branch |33 passes througha heat exchanger |36 where the water is cooled to say 185 and thenenters the previously mentioned manifold 65 for cooling the thermostatbulbs controlling the valves 31. A suitable valve |31 operated by ailoat |33 may be provided to cut oi! the flow of cooling water wheneverthe liquid in the tank 33 reaches a predetermined maximum level. Thisarrangement insures that the receiver will not be flooded.

The heat exchanger |30 may be supplied with a cooling medium in anysuitable manner. In the particular arrangement shown, new water tosupply the water treating apparatus is used. The new water enters theheat'exchanger |33 through a pipe |40 and is carried oil.' to thetreating apparatus by a pipe |4I.

The second branch |35 of the previously mentioned pipe |32 that suppliesthe treated water is provided with a suitable check valve |42 and isconnected to the intake of a boiler feed pump |43. Liquid thataccumulates in the receiver 30 is drawn off by a suitable pump |45, theoutput ot which is carried by a pipe -|43 to the previously mentionedpipe |35. Thus liquid trom the receiver 36 is continually supplied tothe intake of the boiler ieed pump |43. The pump l|43 discharges into aboiler line |41 which has a number of branches, there being six branches|43 leading to the six previously mentioned return line heat exchangers|3| respectively and one branch |49 that by-passes all of the heatexchangers. The by-pass branch |49 connects with a pipe |53 that leadsdirectly to the boiler. A pipe 5| is connected to all of the heatexchangers |3| to pick up the cooling water from the heat exchangers fordelivery to the boiler pipe |50.

It will be noted that the duid pumped into the boiler feed line |41 i'orpassage through the various heat exchangers |3| on its way to the boileris make-up water mixed with condensate that has been returned throughthe various return lines 32.

Preferably the branch pipes |40 and |43 are provided with respectivevalves |52, which valves may be individually manipulated to vary therelative amounts oi water that flow through the various heat exchangers|3I. If there is reason for promoting velocity in one or more of thereturn lines |32 relative to the other return lines. the proportion ofcooling water that flows through the corresponding heat exchanger orheat exchangers may be increased accordingly by manipulating theappropriate valve or valves |52.

A further possibility for increasing the velocity of ilow through anyone of the return lines 32 is to adjust the corresponding thermostaticvalve 31 at a higher setting than the rest of the valves to favoropening action of the valve. If desired, flow through any selectedreturn line may be increased relative to the ilow through the remainingreturn lines by resorting to both of these methods of adjusting, that isto say, by increasing the ilow of cooling water through thecorrespending heat exchanger 3| and at the same time raising thetemperature setting of the corresponding thermostat valve 31. Thesettings of the thermostats may be graduated in accord 'with a graduatedseries of rates of ilow or in accord with the quantities oi' condensatew be handled by the various return lines.

Fig. 9 is illustrative of various practices of the invention thatinvolve utilizing steam from the receiver 36. The steam may be largelylive steam drawn through the whole system or may be largely if notentirely, steam generated by the dashing action of condensate as itdrops in pressure on entering the receiver.

Fig. 9 shows the usual master control 3| including the usual receiver33. The various return lines J2 are connected to the usual thermostat-13 controlledvalves 31 and a manifold 66 delivers cooling water to thethermostats as heretofore described.` A suitable pump |53 may beoperated continuously to deliver liquid from` the master control tank 36to a kboiler feed line |55. In the particular arrangement shown,whenever the liquidzcontcnt of the receiver 36 drops toa predeterminedminimum level, a suitable float (not shown) in the tank opens a valve|56 in a` by-pass line |51 from the discharge side of the pump |53 tothe master control tank for recycling of the iluid. This arrangementkeeps the receiver from being pumped dry.

Steam from the receiver 36 in Fig., 9 is continually released through -apipe |58 to a suitable point of use or disposal. A feature of theparticular arrangement shown is that the steam is delivered to a lowpressure steam-consuming device vand the resulting condensate isemployed to cool the thermostat bulbs. In Fig. 9 the pipe |58 carriessteam from the master control tank to a low pressure heater |60 and thecondensate from to the previously mentioned cooling water mani! fold 65.

If desired, one or more expedients may be employed to insure that theliquid delivered to the manifold 65 is relatively cool. Thus Fig. 9shows a pressure reducing valve |63 in the pipe |56 to drop the pressureof the steam supply to the heater |60. Such pressure drop means coolercondensate. A second expedient that may be used is a heat exchanger |65for cooling the condensate as it passes through the manifold 65.Relatively cool water from any suitable source may be circulated throughthe heat exchanger |65 by means of pipes |66.

The various partsof Fig. 9 described up to this point may constitute apractical embodiment of the invention as will now be explained. Thepressure in the receiver 36 will be determined on the one hand, by therate at which fluid enters the receiver through thethermostat-controlled valves 31 together with the rate of inflow fromthe cooling manifold 65 and, on the other. hand, by the rate at whichsteam is drawn off -by the pipe |58. It is contemplated that the rate ofwithdrawal of steam from the receiver 36 through the pipe |58 will besuitably controlled to maintain the pressure in the master control tankin a selected range of pressures that the thermostat valves 31 will beadjusted to operate within the range of temperatures corresponding tothat range of pressure. Preferably the settings of the variousthermostat valves 31 will be graduated in accord with the condensateloads on the corresponding return lines 32, the higher the condensateload the higher being the setting of the corresponding thermostat valve.

For any given rateof fluid withdrawal from the receiver 36 by thecondensate pump |53 and the steam line |58 the various thermostat valves31 will release fluid from the return lines 32 at relative ratesdetermined by the relative settings of the thermostat valves. The totalrelease from the return lines under steady state conditions will tend tomaintain some given equilibrium pressure with receiver. In practice theseveral thermostat settings must not extend over too wide a ran-geotherwise the pressure in the master control tank will be sustained bythe thermostat valves with the higher settings and the thermostat valveswith the lower settings will not open at all.

The supply side of a steam system represented by Fig. 9 may be at 40lbs. per square inch gauge.

'14 The pressure in the returnlines 32 may be approximately 35 lbs. andthe pressure in the receiver 36 may be in the range of 10A to` 30 lbs.gauge. If, for example, the master control tank is at' 36 lbs., thepressure reducingvalve |63 may ser've to drop that pressure toapproximately 12 lbs. gauge. l

The plurality of. thermostat valves 31 will respond automatically to anychanges in therate of iluid .released from the master control tank.Suppose, for example, that a state of equilibrium exists with a constantrelease of iluid from the tank and that the pressure in the tank is at30 Conversely, if for any reason the rate of fluid 'release from thereceiver is decreased, the -pressure s in the receiver will rise to anew equililorium and this heater is delivered by a suitable pump |62 f'release from the return lines.

the consequent higher temperature in the receiver will cause thethermostat -valves to' reduce4 the Fach thermostat -valve l respondsdirectly only to temperature changes as-distinguished from pressurechanges, butternperature in the receiver varies directly with steampressure so that the valves respond indirectly to pressure changes. i y

It is to be understood thatin all instances the thermostat may be slowacting or quick acting and may completely close or only partially close.

In some practices of the invention steam may be released from thereceiver 36 through a pipe |61 leading to a remote deaerator tank |10,the release through the pipe |61 either supplementing the releasethrough the pipe |58 `or replacing the release through the pip |58.

In Fig. 9 the master control tank is shown diatgrammatieally in plan butthe deaerator is shown diagrammatically in elevation. The layout indi--cated in Fig. 9 is suggested for steam plants in which the logical andconvenient point for the collection of condensate by a receiver is aconsiderable distance from the boiler room where deaeration requiringconsiderable steam is carried out. The demand for steam for deaerationis met in part bythe steam from the receiver.

In the particular arrangement shown in Fig. 9, thelpipe |61 forconveying steam from the mas-- ter control tank 36 is connected to akheat exchanger |1| in the boiler room and the heat exchanger in turn isconnected to the deaerator tank |10 by a pipe |12, the connection beingabove the liquid level in the deaerator tank. Cold water for make-up issupplied through a pipe |13, having a valve H5 that responds to a oatcontrol |16 on fthe deaerator tank. The water flows through a condenserv|11 for condensing vapors inthe upper end of the tank and then passesthrough a pipe |18 to a coil |80 inside the heat exchanger |1|. From thecoil |80 the heated water is carried by a pipe |8| to a spray head |82inside the deaerator tank above thepoint of discharge of the previouslymentioned pipe |12. This spray head has downwardly directed sprayopenings so that the released water is directed towards the condensateor condensate and steam that is discharged from the pipe |12.

The deaerator tank |10 has at the top a relief pipe |15 controlled by arelief or safety valve |15 atmosphere may be a simple manual valve thatis adjusted from time to time as required to permit continuous releaseof fluid at a rate to maintain a desired approximate nornal pressure inthe deaerator tank. It is contemplated that the arrangement and thevarious adjustments will be such that the fluid escaping to theatmosphere through the -vent pipe |81 willI be mostly, if not entirelymore condensible gases isolated by the deaeration action.

Fig. 9 shows a pair of boiler feed pumps |90 and |9| connected inparallel to the bottom of the deaerator tank |10 by a pipe |93. The twopumps, one of which will serve as a stand-by pump, are connected tocommon discharge pipe |93 leading to the previously mentioned boilerfeed line |55. If desired, a valve |95 in a by-pass pipe |96 may beopened to cause condensate from the receiver 36 to be delivered to thedeaerator tank |10 instead of directly to the boilers. Also if desired avalve |91 in a by-pass pipe |90 may be opened to cause the cold watersupply to go directly to the intake sides of the boiler feed pumps |90and |9| instead of directly to the deaerator tank |10.

It is assumed in Fig. 9 that the pressure drop between the receiver 36and the deaerator tank |10 caused by the relatively long pipe |61, theheat exchanger |1|, and the pipe |12 will be such that the relativepressures in the two tanks will be at desired values. If a greaterpressure difference is required than can be provided by-normal flowresistance, a greater pressure drop may be provided by usingrestrictions or using a pressure reducing valve, which expedients areweil known to the art.

In one instance, by way of example, the pressure in the receiver 86 maybe 10 lbs. gauge and the pressure in the deaerator tank 5 lbs. gaugewith a pressure drop of 5 lbs. between the two tanks and a finalpressure drop of 5 pounds across the partially opened vent valve |86.Preferably the deaerator tank is provided with' a suitable pressuregauge 200 for guidance in adjusting the valve |86. In other instancesthe pressure in the master contro1 tank may be relatively high, say 30or 40 lbs. gauge, for the sake of direct return of condensate to theboiler without substantial reduction in the pressure of the condensate.

The deaeration action in the tank |10 is well known operation. The newlyintroduced water is heated in two stages: rst, in the condenser |11 andsecond, in the coils |80 of the heat exchanger |1|. The water reachesthe spray head |92 at relatively high temperature and at greaterpressure than the pressure prevailing in the deaerator tank.

The release of the heated Water through the spray openings into theregion of lower pressure causes separation of non-condensible gases fromthe water and further separation occurs as the spray encounters theheated discharge from the pipe |12. The cooling action of the spray issuch as to condense substantially all the vapors released by the pipe|12 and any residual vapors that exist are turned into water by thecondenser.

Fig. 10 illustrates diagrammatically another practice of the inventionin which steam is continually drawn from the master control tank at arate to maintain a predetermined pressure or range of pressures therein.The concept here is 18 steam from the master control receiver 86 throughthe supply header 208.

High pressure steam from a high pressure supply line 281 is supplied tothe high pressure inlet of the jet-compressor 208 for discharge from anenclosed Jet nozzle 208 (Fig. l1) into a Venturi throat 2|0. Steam fromthe receiver'36 is carried by a pipe 2|| to the low pressure inlet ofthe iet-compressor 205 for intermixture with the high pressure steam inthe venturi. The

discharge from the jet-compressor 205 is carried by a pipe 2|2 to thesupply header 206. The header 208 feeds the various cylindrical driers|0 which are constructed and arranged as heretofore described.

The driers |8 are grouped in the usual manner for delivering condensateto the receiver through a plurality of return lines. Fig. 10 shows areturn header I8 connected to one of the return lines 82 and showsfragments of the remaining return lines. Each of the return lines 92 iscontrolled by the usual thermostat valve 31, and if desired, each of thethermostats may be supplied with relatively cool water to favor openingaction of the valve as heretofore described. Condensate is continuallywithdrawn from the receiver 36 by the usual pump 42.

As an example of operating conditions, steam supplied to theJet-compressor 205 through the pipe 201 may be at lbs. gauge and thereceiver 36 may supply steam at approximately 40 lbs. gauge. Thejet-compressor will supply steam to the header 208 at some intermediatevalue, say 60 lbs. gauge.

Preferably some provision is made for maintaining the desired pressurerelationships automatically. For this purpose, Fig. 10 shows a pressureregulator 2|8 in the high pressure steam line 201. Atube 2|6 extendsfrom the pressure regulator 2|8 for response to the discharge side ofthe jet-compressor 206 so that the pressure regulator may maintain apredetermined pressure differential across the jet-compressor. Inaddition, a suitable ipressure reducing valve 2|6 may be inserted in thepipe 2| to release steam from the receiver 86 at a controlled rate thatwill insure maintenance of the desired back pressure in the receiver.

We claim as our invention:

1. In a steam system, at least one steam using device, a steam supplyconnected with the inlet side of said device, a closed receiver, areturn line from the outlet of said device to said receiver to carryfluid thereto, a valve controlling release of fluid from said returnline into said receiver, said device and return line forming acontinuous open channel from said steam supply to said valve, athermostat operatively connected to said valve to cause opening actionof the valve at temperatures below the thermostat setting and closingaction of the valve at temperatures above the thermostat setting, saidtheromstat being positioned to be heated by the fluid released by saidvalve and having a setting above the temperature prevailing in saidreceiver and below the temperature prevailing in said return line, adevice using steam at a lower pressure than said steam supply, means tosupply flash steam from said receiver to said low pressure device andmeans to convey the condensate from said low pressure device into heatexchange relation with said thermostat for cooling of the thermostat.

2. In a steam system, a combination as set forth in claim l in whichsaid valve discharges to employ a jet-compressor 205 to recycle the 18into a passage leading to spray openings in said 17 receiver and inwhich said thermostat is positioned in said passage. i

3. In a steamV system, a combination as set forth in claim 1 in whichmeans is provided to reduce the pressure of the steam suppliedto saidlow wpressure device substantially below the pressurein said receiver.

4. In a steam system, a combination as set forth in claim 1 in whichheat exchange means is provided to cool the condensate before thecondensate reaches said thermostat/ 5. In a steam system, a plurality ofsteam using devices, a steam supply connected with the inlet sides ofsaid devices, a receiver-under substantially less pressure than saidsteam supply, a plurality 'of`return lines from said devices to', saidreceiver, a valve controlling the release of fluid from each of saidreturn lines into said receiver, said devices and return lines formingcontinuous open channels from said steam supply to said valve, athermostat operatively connected to each of said valves, said thermostatbeing positioned to be heated by the fluid released by the valve, saidthermostat having a temperature setting above which it causes closingaction of the valve and below which it causes opening action of thevalve, said setting being below the temperaturein the correspondingreturn line but above the temperature in the receiver, the settingsl ofsaid thermostats being varied in accord with desired relative rates offlow in said return lines, and means to deliver uid from said receiverat a rate to maintain the pressure and temperature therein below thepressure and temperature in said return lines.

6. In a steam system, a combination as set forth in claim 5 whichincludes means to apply a cooling fluid to said thermostats.

7. In a steam system, a combination as set forth in claim 5 in whicheach of said valves discharges into a-corresponding passage leading to.

the release of fluid from each of said return lines into said receiver,said steam using devices and return lines forming continuous openchannels from said steam supply to said valves, a thermostat operativelyconnected to each of said valves, said thermostat being positioned to beheated by the fluid released by the valve, said thermostat having atemperature setting above which it causes closing action of the valve,and below which it causes opening action of the valve, said settingbeing below the temperature in the corresponding return line but abovethe temperature in the receiver, a plurality of passages correspondingto said thermostats for conducting cooling fluid into heatexchangerelation with the thermostats to cause opening action of thecorresponding valves, and a plurality of valve means for varying theflow of the cooling fluid through said passages.

9; In a steam system, a plurality of steam using devices, a steam supplyconnected with the inlet l side of said devices, a receiver, a pluralityof return lines for conveying uid from said devices 4steam supplyto'saidvalves, a thermostat operatively connected to each of said valves. saidthermostat being positioned to be heated by the fluid released by thevalve, said thermostat having a temperature setting above which itcauses closing action of the valve and below which it lli/causes openingaction of the valve, said setting being below the temperature in thecorresponding return line but above the temperature in the receiver, andmeans to draw fluid from said receiver at -a rate to maintain thedesired pressure therein.

19. In a steam system, a combination as set forth in claim 9 whichincludes means to apply a cooling fluid to each of said thermostats.

11. I n a steam system, a plurality of steam using devices, a steamsupply connected with the inlet sides of said devices, a closedreceiver, la plurality of return lines from said devices to saidreceiver, a valve controlling the release of iluid from each of saidreturn lines into ,said receiver, said steam using devices and returnlines forming continuous' open kchannels from said steam supply to saidvalves, a thermostat operatively connected to each of said valves, saidthermostat being positioned to be heated by the fluid released by thevalve, said thermostat having a temperature setting above which itcauses closing action of the valve and below which it causes openingaction of the valve, said setting being below the temperature in thecorresponding return line but above the temperature in the receiver, andmeans to draw flash steam from said receiver at a rate to maintain thepressure of the receiver Within a given range below the pressureprevailing in said return lines.

12. In a steam system, a plurality of steam using devices, a steamsupply connected with the inlet sides of said devices, a closedreceiver, a

plurality of return lines from said devices to said receiver, a valvecontrolling the release of fluid from each of said return lines intosaid receiver, said steam using devices and return lines formingcontinuous open channels from said steam supply to said valves, athermostat operatively connected to each of said valves, said thermostatbeing positioned to be heated by the fluid released by the valve, saidthermostat having a temperature setting above which it causes closingaction of the valve and below which it causes opening action of thevalve, said setting being below the temperature in the correspondingreturn line but above the temperature in the receiver, a deaerator tankremote from said receiver, means to remove flash vapor from saiddischarges into a corresponding passage leading to spray openings insaid receiver and in which the corresponding thermostat is positioned insaid corresponding passage.

14. In a steam system, at least one, steam using device, a steam supply,a jet-compressor having a discharge outlet connected to the inlet sidesof said devices, a high pressure inlet connected with said supply and alow pressure inlet, a closed receiver, a return line from the outlet ofsaid device'to said receiver to carry fluid thereto. a

valve controlling release oi fluid from said re- I turn line into saidreceiver, said devices and return line forming a continuous open channelfrom said jet-compressor to said valve, a thermostat operativelyconnected to said valve to cause opening action of the valve attemperatures below the thermostat setting and closing action of thevalve at temperatures above thev thermostat setting, said thermostatbeing positioned to be heated by the iiuid released by said valve andhaving a setting above the temperature inl said receiver and below thetemperature in said return line, means to convey steam from saidreceiver to said low pressure intake of the jet-compressor and means wrelease condensate from said receiver.

15. In a steam system, a combination as set forth in claim 14 whichincludes means to apply a cooling iluid to said thermostat.

Elim PAUL HARRISON.

ORVIILE A. HUNT.

LOUIN TRIER.

REFERENCES CITED The following references are of record in the nie ofthis patent:

UNITED sTATns PATENTS 5 lines.

15 Number Name Date 2,001,344 Fielder May 14. 1938 2.321.235 Olson June8, 1943 2,386,332 Harrison et al Jan. 2. 1945

